This application relates to position-defining and energy-isolating mountings. In particular it relates to mountings used to mount transducers such as acoustic emitters and/or detectors within a system used for three-dimensional coordinate determination adapted, in particular, for automotive crash repair and diagnostics.
An example of the application of the position-defining and energy-isolating mountings is in vehicle shape-determination systems of the kind disclosed in WO 93/04381, in which the present position-defining and energy-isolating mountings provides a mounting of the kind required for the array of microphones (18) which are mounted with respect to a beam (10) for use in the manner briefly disclosed and illustrated in data items (54) and (57) on the front page of the above-identified WO publication.
A similar such vehicle shape determination system is also described in European Patent EP 0,244,513 (and corresponding US patent U.S. Pat. No. 4,811,250). In EP 0 224 513 B1 (Applied Power Inc/Steber) a system for acoustic-based three-dimensional coordinate analysis as applied to automotive vehicles is described. In this system acoustic signals from transmitter means at a series of defined locations are received by acoustic receiver means. The receiver/transmitter means are located at a series temporarily fixed separated locations throughout a series of measurements, and signals received are sent to data processing means whereby a time-based determination of the coordinates of each of the reference locations is made by a calculation technique utilising the acoustic signal transmission time differential for two transmitters at each  location of known spacing from each other at that location, and by reference to a simple triangulation technique. There are also numerous other published specifications and examples of such systems in which arrays of emitters/sensors, are mounted on a fixed frame and interact with cooperating sensors/emitters which are positioned at reference positions relative to the shape to be determined, with data processing means interpreting the signals sensed by the sensors in order to determine the relative positional information.
In the case of existing mountings for the emitters and/or detectors the kind used in the above techniques with which the present position-defining and energy-isolating mountings is concerned, such as miniature microphones, the current assumption is that in such mountings a degree of vibration damping should be provided and that the microphones should be vibration isolated from the beam of frame within which they are placed. In addition the miniature microphones require accurate placement, ease of mounting, ease of dismounting or replacement, and a degree of physical shielding from impact or similar damage. These requirements should all be provided and met by the mounting. Accordingly the currently available solution to this interplay of (to some extent) conflicting physical requirements on the mounting has been to use a mounting of a two-piece construction in which an elastomeric bushing envelops the microphone itself and serves to provide vibration isolation of the microphone and damage protection. Then, in order to meet the requirement for relatively accurate position definition for the microphone there is additionally provided a metallic collar around the elastomeric bushing. The collar serves to engage the beam on which the array of microphones are mounted and thus serves to position relatively accurately the collar itself with respect to the beam and through the interaction (via  adherence) of the collar with the elastomeric bushing, the collar exerts a degree of position control on the microphone itself.
With such a mounting insertion of the microphone into the bushing and collar assembly is achieved by means of an end-insertion technique in which a projecting length of microphone conductor (and associated electrical shielding) is inserted through the bushing and through its associated end cable holder, and is then caused to fit snugly into the main body of the bushing. There is a further means for achieving this by tensioning the conductor. In other words, the microphone is pulled into its bushing by its lead. This can readily cause damage to the electrical connection to the microphone.
Other shortcomings of the previously-used microphone mounting system include the lack of accuracy of positional and/or orientational placement of the microphone due to the inherent ineffective transmission of position information through the elastomeric bushing from the mounting collar.
Additionally, the mounting process is relatively difficult due to frictional effects arising during the endwise insertion process, particularly if the assembly person is conscious of the need not to damage the electrical connections to the microphone.
There is also a need for a provision of means, in the case of mountings of the general kind disclosed herein, for accommodating a degree of non-circularity (such as ovality) in the mounting openings provided in the support for the acoustic emitter or detector or other sensor, without prejudicing the accuracy of mounting. In general terms, the matching of a circular fitting to a circular receptor is not readily achievable in practical circumstances in relation to field-used  articles of this kind without difficulties and/or costs and some improvements in this respect are needed.
It is noted that vibration damping and isolating mounting arrangements are used in other fields and to mount other components. Such arrangements are described in, the following published patent specifications: WO 98/12453, GB 2046,401, GB 1,498,891; GB 1,289,746; GB 845,891; U.S. Pat. No. 5,013,166; and GB 1,169,688. These prior arrangements all use an elastomeric material, predominantly rubber, within the mounting in order to sufficiently isolate the mounted component from the structure to which it is attached. In a further prior patent GB 1,178,927 the mounting provides the required degree of resilience, as would be expected from an elastomeric material, by using sufficiently thin resilient arms members/straps to support the mounted component.
While such arrangements are similar to the above described current mounting of the microphones, in that they provide vibration isolation using elastomeric materials (or mimic the resilience of such materials), it should be recognized that the requirements for mounting a sensitive electronic component like a microphone are very different. Also the specific requirements of the mounting dictated by above system within which the microphone forms a key part, are very different from the components and arrangements with which these prior mounting patents are concerned. The prior patents relating to mounting structural floor panels, torsion bars and pipes etc. 